Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true and openWorldHint=true. The description adds meaningful behavioral context: traffic values are Internet-only and scoped to the current traffic month with used_gb, limit_gb, and period_ends_at, plus the vms.read permission scope. It does not cover error behavior or whether suspended machines are returned differently.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is compact, front-loaded with the resource and returned fields, and avoids repetition. The parenthetical traffic details are dense but earn their place by clarifying a non-obvious scoping rule.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description usefully enumerates the main returned fields and traffic semantics. For a simple single-parameter read tool with read-only annotations, this is largely complete, though it omits not-found behavior and return structure details.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, and the single vm parameter is already documented as 'Machine id, as returned by list_vms or create_vm.' The description adds no further parameter semantics beyond what the schema provides, so baseline 3 is appropriate.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states it retrieves a single machine and enumerates the returned data (status, IPs, specs, traffic, billing, suspension). It does not explicitly contrast with list_vms or get_vm_metrics, but the resource and scope are easy to distinguish.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The phrase 'One machine' implies single-resource retrieval vs. a list operation, and 'Scope: vms.read' gives permission context. However, it never explicitly says when to use this instead of list_vms, get_vm_metrics, or get_vm_network, so usage is only implied.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.